1. Technical Field
The present invention relates to hand tools, and more particularly, to a driving shaft mechanism designed for a ratchet wrench and having a lighting device therein.
2. Description of Related Art
Conventionally, when using a ratchet wrench to assemble or disassemble fixing elements in dark or under conditions of poor illumination, a user needs to hold a light in one hand while a hand tool in the other for lighting up an operating area. However, it is indeed troublesome if it takes both hands to operate in assembling or disassembling tasks. That means the user needs to install the light in a proper place and keep the light directed to the operating area during assembling or disassembling tasks.
For overcoming aforesaid shortcomings, some has developed hand tools integrated with a lighting device, as indicated in a number of prior arts. For example, Taiwan Utility Model Patent No. 287727 discloses a lighting device built in a grip of a hand tool to present downward a light beam. Another two prior arts, Taiwan Utility Model Patent Nos. 194208 and 181988, have a lighting device set within a grip of a hand tool and the light emits toward a working end of the hand tool. Still another Taiwan Utility Model Patent No. 189542 has a lighting device set outside a grip of a hand tool with its light cast toward a working end of the hand tool.
As discussed above, said prior arts do not have the light cast directly onto an operating area, thus leaving the operating area dark for the purpose of operation or bring shadowed by a user's hand or anything else between the light source and the operating area.
In yet another prior art, Taiwan Utility Model Patent No. 151015, a lighting unit established at a working end of a ratchet wrench provides direct lighting toward an operating area of the ratchet wrench. Unfortunately, it is uneconomic to build such a lighting unit inside a metal ratchet spindle due to a highly increased cost resulting from an additional drilling process to make a spindle bore in the spindle for accommodating the lighting unit. In addition, the lighting unit composed of a lamp, an electric pin and an electric conductor slackly positioned in the spindle bore is likely to have its components loosening, thereby causing poor connection.
In sum, during operating aforesaid ratchet wrench, an accidental switch-off of the lighting device or unit caused by the user's hands or other articles may easily occur and result in danger because the lighting device or unit is triggered by a simple slide or rotation to a switch correspondingly controlling the lighting device or unit. In addition, the operating area may not be fully covered by the light emitting from the lighting device, and an expensive cost and a technically challenging installation may attribute to complicated structure or excess parts.